I've been rolling around the idea of getting a bergara HMR in 6.5 CM, and cutting the barrel down to 16.5" (down from 22") 

According to the calculator and some tests from others online, a 123 SMK would stay super sonic to ~1,200 yards and would maintain at least 1k Ft/lb of energy out to 400 out of a 16.5" with a MV of 2625

My assumption is that I will get .308ish (or better) performance (given equal barrels of 16.5") for hunting within ~400 yards, and much better long range performance because 6.5

Have any of you experimented something similar to this? Barrels between 14.5" and I guess like 18"? 

Not much different than a long barrel 6.5 Grendel and everone knows 6.5Grendel is the best cartridge on planet earth and a few others.

I don't see why not. Make it how you want.

I do shoot the 6.5Grendel with long bbl(24"), I shoot 140s, they work great. My mag length 140 load is 2300fps my single feed 140 load is 2480fps both work great.
My 90gr load is 2850.

I'm in the process of a 16.5" 6.5CM project. I wanted something short to suppress and hunt with. I was going to do a 243 but decided to go up to 6.5. For the ranges I'll use it at I'm not too worried about velocity.

I still need to fit the stock a little and bed it. Attached File
Attached File

I just had my Tikka fitted with an 18" Bartlein. Should have it out to the range for the first time this Wednesday.

I hoping to get 2650+ with Berger 130 Hybrids. That would be supersonic past 1000 with 78" of drift, and 1000 ft-lbs to almost 600 yards.

Once I get it out to the range I will post up a range report.

Tag.

I want a 18 - 20" for my rpr

Ok finally got the new 18" Creedmoor out to the range today.

Tikka T3
18" 6.5C Bartlein barrel, Varmint/Sendero Profile.
Manners EH-T stock
Yo-Dave trigger spring

Nightforce NXS 2.5-10x42
Nightforce 20MOA base
Nightforce Ultralight Rings

SiCo Omega





Put a total of 65 rounds down the tube today. Started with a couple boxes of factory loaded Hornady 140 ELD-M.

After initial sight-in, I fired seven 5-round groups at 100 yards and completed an abbreviated break in procedure.  

Extreme spreads in order
1.048"
1.281"
.962"
-----Break-in procedure complete----
.874"
.603"
.922"
.815"

I also took velocity measurements on the last two five round groups.

First group averaged 2574 ft/s, second group 2589 ft/s.



Ended the day by firing some hand loads using Alpha brass, 130 Berger AR Hybrids and H4350. Accuracy wasn't great and I will have to mess with seating depth/neck tension but velocity was promising.

Powder loads - Velocity
41.0 - 2604
41.5 - 2650
42.0 - 2692
42.5 - 2721

I was reading where a company out of vegas was getting good results with a short 6.5 Creedmoor. they were using IMR 8208xbr and getting respectable velocity back with the 120-130gr class of bullets. was sin city tactical or something of that sort.

here it is.
http://www.sincityprecision.com/short-barrel-6-5mm-rifle/
http://www.sincityprecision.com/follow-up-short-barrel-6-5mm-rifle/

You should have no problem getting that speed with an 18" CM and 130s.

A 20" 6.5 Grendel bolt gun will push 129gr IB to 2650fps using CFE223, been done already.

If you use my 130gr VLD load, you'll get 2709fps from an 18" Creedmoor.

Try working in .4gr increments with 6.5 CM since it is about a 40gr usable capacity case.

130gr ELD-M is what I would shoot since it is much cheaper, G7 BC is about the same, also works as an excellent hunting bullet.  More trigger time for the price.

Your results are right where I would expect them to be for a 130gr.

120-130gr is the money for 6.5-08 class of cartridges for me.  TOF is laser-like, and trajectory is flat as can be.  Speed brings the drift right within .1 mils of 140gr.

Sin City Precision.

Dane Miller is a founding member and also builds rifles as DMR Rifles. Him and another local have been playing with shorty 6.5's for a few years.

Dane and his new shorty build. Tikka action in XLR Element with 16" Benchmark.



Joe Comfort's brand new 16" build on a Stiller action in a Mirage ULR chassis with Delta P Brevis can.



Joe is looking at running 140 class stuff in his. In the past they stuck with 123 Scenars. I'm going out with him this weekend to do some chrono testing. I'm interested to see what the 140's will do.